CDNI Working Group                                         F. Fieau, Ed.
Internet-Draft                                                E. Stephan
Intended status: Standards Track                                  Orange
Expires: 12 January 2023                                       S. Mishra
                                                                 Verizon
                                                            11 July 2022


                  CDNI extensions for HTTPS delegation
             draft-ietf-cdni-interfaces-https-delegation-09

Abstract

   This document defines a new Footprint and Capabilities metadata
   objects to support HTTPS delegation between two or more
   interconnected CDNs.  Specifically, this document outlines CDNI
   Metadata interface objects for delegation method as published in the
   ACME-STAR document [RFC9115].

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 12 January 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.











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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Delegation metadata for CDNI FCI  . . . . . . . . . . . . . .   3
   4.  Delegation metadata for CDNI  . . . . . . . . . . . . . . . .   4
     4.1.  Usage example related to an HostMatch object  . . . . . .   4
     4.2.  AcmeStarDelegationMethod object . . . . . . . . . . . . .   5
   5.  IANA considerations . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  CDNI MI AcmeStarDelegationMethod Payload Type . . . . . .   7
     5.2.  CDNI FCI SupportedDelegationMethods Payload Type  . . . .   7
   6.  Security considerations . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Content delivery over HTTPS using one or more CDNs along the path
   requires credential management.  This specifically applies when an
   entity delegates delivery of encrypted content to another trusted
   entity.

   [RFC9115] defines a mechanism where an upstream entity, that is,
   holder of a X.509 certificate can give a temporary delegated
   authority, via issuing a certificate to one or more downstream
   entities for the purposes of delivering content on its behalf.
   Furthermore, the upstream entity has the ability to extend the
   duration of the certificate automatically and iteratively until it
   allows the last renewal to end and therefore terminate the use of
   certificate authority to the downstream entity.










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   More specifically, [RFC9115] defines a process where the upstream
   Content Delivery Network (uCDN), the holder of the domain, generates
   on-demand a X.509 certificate for the downstream CDN (dCDN).  The
   certificate generation process ensures that the certified public key
   corresponds to a private key controlled by the downstream CDN.
   [RFC9115] follows [RFC8739] for Short-Term, Automatically Renewed
   Certificate (STAR) in the Automated Certificate Management
   Environment (ACME).

   This document defines CDNI Metadata to make use of HTTPS delegation
   between an upstream CDN (uCDN) and a downstream CDN (dCDN) based on
   mechanism specified in [RFC9115].  Furthermore, it includes a
   proposal of IANA registry to enable adding of delegation methods.

   Section 2 defines terminology used in this document.  Section 3
   presents delegation metadata for the FCI interface.  Section 4
   addresses the metadata for handling HTTPS delegation with the
   Metadata Interface.  Section 5 addresses IANA registry for delegation
   methods.  Section 6 covers the security considerations.

2.  Terminology

   This document uses terminology from CDNI framework documents such as:
   CDNI framework document [RFC7336], CDNI requirements [RFC7337] and
   CDNI interface specifications documents: CDNI Metadata interface
   [RFC8006] and CDNI Footprint and capabilities [RFC8008].

3.  Delegation metadata for CDNI FCI

   The Footprint and Capabilities interface as defined in [RFC8008],
   allows a dCDN to send a FCI capability type object to a uCDN.  This
   draft adds an object named FCI.SupportedDelegationMethods.

   This object shall allow a dCDN to advertise the capabilities
   regarding the supported delegation methods and their configuration.

   The following is an example of the supported delegated methods
   capability object for a CDN supporting STAR delegation method.













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        {
        "capabilities": [
          {
            "capability-type": "FCI.SupportedDelegationMethods",
            "capability-value": {
              "delegation-methods": [
                       "AcmeStarDelegationDelegationMethod",
                       "... Other supported delegation methods ..."
              ]
            }
            "footprints": [
              <Footprint objects>
            ]
          }
         ]
        }

4.  Delegation metadata for CDNI

   This section defines Delegation metadata using the current Metadata
   interface model.  This allows bootstrapping delegation methods
   between a uCDN and a delegate dCDN.

4.1.  Usage example related to an HostMatch object

   This section presents the use of CDNI Delegation metadata to apply to
   an HostMatch object, as defined in [RFC8006] and as specified in the
   following sections.

   The existence of delegation method in the CDNI metadata Object shall
   enable the use of this method, as chosen by the delegating entity.
   In the case of an HostMatch object, the delegation method will be
   activated for the set of Host defined in the HostMatch.  See
   Section 4.2 for more details about delegation methods metadata
   specification.

   The HostMatch object can reference a host metadata that points at the
   delegation information.  Delegation metadata are added to a Metadata
   object.

   Those "delegation" metadata can apply to other MI objects such as
   PathMatch object metadata.

   Below shows both HostMatch and its Metadata related to a host, for
   example, here is a HostMatch object referencing "video.example.com":






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   HostMatch:
      {
        "host": "video.example.com",
        "host-metadata": {
          "type": "MI.HostMetadata",
          "href": "https://metadata.ucdn.example/host1234"
        }
      }

   Following the example above, the metadata is modeled
   for ACMEStarDelegationMethod as follows:

     "generic-metadata-value": {
       "acme-delegations": [
         "https://acme.ucdn.example/acme/delegation/ogfr8EcolOT",
         "https://acme.ucdn.example/acme/delegation/wSi5Lbb61E4"
       ]
     }

4.2.  AcmeStarDelegationMethod object

   This section defines the AcmeStarDelegationMethod object which
   describes metadata related to the use of ACME/STAR API presented in
   [RFC9115]

   As expressed in [RFC9115], when an origin has set a delegation to a
   specific domain (i.e. dCDN), the dCDN should present to the end-user
   client, a short-term certificate bound to the master certificate.























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dCDN                  uCDN             Content Provider           CA
 |              ACME/STAR proxy        ACME/STAR client    ACME/STAR srv
 |                     |                     |                     |
 | 1. GET Metadata incl. Delegation Method object with CSR template|
 +-------------------->|                     |                     |
 | 200 OK + Metadata incl. CSR template [CDNI]                     |
 |<--------------------+                     |                     |
 | 2. Request delegation: video.dcdn.example + dCDN public key     |
 +-------------------->|                     |                     |
 |                     | 3. Request STAR Cert + dCDN public key    |
 |                     +-------------------->| 4. Request STAR cert|
 |                     |                     |    + Pubkey         |
 |                     |                     |-------------------->|
 |                     |                     | 5. STAR certificate |
 |                     | 6. STAR certificate |<--------------------|
 | 7. STAR certificate |<--------------------+                     |
 +<--------------------|                     |                     |
 |                     |                     |                     |
 | 8. Retrieve STAR certificate (credential-location-uri)          |
 +---------------------------------------------------------------->|
 |                     |                     |         9. renew +--|
 |                     |                     |            cert  |  |
 | 10. Star certificate                      |                  +->|
 |<----------------------------------------------------------------+
 |  ...                |                     |                     |

Figure 1: Example call-flow of STAR delegation in CDNI showing 2 levels
of delegation

   Property: acme-delegations

      Description: an array of delegation objects associated with the
      dCDN account on the uCDN ACME server (see Section 2.3.1 of
      [RFC9115] for the details).

      Type: Objects

      Mandatory-to-Specify: Yes

5.  IANA considerations

   This document requests the registration of the following entries
   under the "CDNI Payload Types" registry hosted by IANA regarding
   "CDNI delegation":







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   +-------------------------------+---------------+
   | Payload Type                  | Specification |
   +-------------------------------+---------------+
   | MI.AcmeStarDelegationMethod   | RFCthis       |
   +-------------------------------+---------------+
   | FCI.SupportedDelegationMethods| RFCthis       |
   +-------------------------------+---------------+

   [RFC Editor: Please replace RFCthis with the published RFC number for
      this document.]



5.1.  CDNI MI AcmeStarDelegationMethod Payload Type

   Purpose: The purpose of this Payload Type is to distinguish
   AcmeStarDelegationMethod MI objects (and any associated capability
   advertisement)

   Interface: MI

   Encoding: see Section 5

5.2.  CDNI FCI SupportedDelegationMethods Payload Type

   Purpose: The purpose of this Payload Type is to distinguish
   SupportedDelegationMethods FCI objects (and any associated capability
   advertisement)

   Interface: FCI

   Encoding: see Section 4

6.  Security considerations

   Delegation metadata proposed here do not alter nor change Security
   Considerations as outlined in the following RFCs: An Automatic
   Certificate Management Environment (ACME) Profile for Generating
   Delegated Certificates [RFC9115]; the CDNI Metadata [RFC8006] and
   CDNI Footprint and Capabilities [RFC8008].

7.  References

7.1.  Normative References







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   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
              "Content Delivery Network Interconnection (CDNI)
              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
              <https://www.rfc-editor.org/info/rfc8006>.

   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
              R., and K. Ma, "Content Delivery Network Interconnection
              (CDNI) Request Routing: Footprint and Capabilities
              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
              <https://www.rfc-editor.org/info/rfc8008>.

   [RFC8739]  Sheffer, Y., Lopez, D., Gonzalez de Dios, O., Pastor
              Perales, A., and T. Fossati, "Support for Short-Term,
              Automatically Renewed (STAR) Certificates in the Automated
              Certificate Management Environment (ACME)", RFC 8739,
              DOI 10.17487/RFC8739, March 2020,
              <https://www.rfc-editor.org/info/rfc8739>.

   [RFC9115]  Sheffer, Y., López, D., Pastor Perales, A., and T.
              Fossati, "An Automatic Certificate Management Environment
              (ACME) Profile for Generating Delegated Certificates",
              RFC 9115, DOI 10.17487/RFC9115, September 2021,
              <https://www.rfc-editor.org/info/rfc9115>.

7.2.  Informative References

   [RFC7336]  Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
              "Framework for Content Distribution Network
              Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
              August 2014, <https://www.rfc-editor.org/info/rfc7336>.

   [RFC7337]  Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
              Network Interconnection (CDNI) Requirements", RFC 7337,
              DOI 10.17487/RFC7337, August 2014,
              <https://www.rfc-editor.org/info/rfc7337>.

Authors' Addresses

   Frederic Fieau (editor)
   Orange
   40-48, avenue de la Republique
   92320 Chatillon
   France
   Email: frederic.fieau@orange.com







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   Emile Stephan
   Orange
   2, avenue Pierre Marzin
   22300 Lannion
   France
   Email: emile.stephan@orange.com


   Sanjay Mishra
   Verizon
   13100 Columbia Pike
   Silver Spring,  MD 20904
   United States of America
   Email: sanjay.mishra@verizon.com





































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